The present invention relates generally to the oscillator art, and more specifically concerns a power oscillator capable of driving a wide range of loads without adversely affecting the output.
Most electrical instruments and similar apparatuses are designed to operate adequately on line voltage. For some, however, the line voltage is not adequate, because the waveform is not sufficiently uniform and contains frequent distortions, although the frequency of the signal is usually sufficiently well-regulated. The non-uniformity of the waveform and the waveform distortions, usually in the forms of small peaks, interfere with the proper functioning of the instrument and in some cases cause erroneous output information.
The electronic test instrument which is the subject of U.S. Pat. No. 4,074,195, issued Feb. 14, 1978, titled "Semi-Conductor Tester," is an example of an instrument which can be adversely affected in operation by distortions in the line signal. Other test instruments and devices have similar operating problems with the line signal. One alternative is a separate, self-contained AC voltage supply, i.e. an oscillator. However, many devices which have difficulty operating with the line signal also must operate over a wide range of loads, and most conventional oscillators are not able to drive into heavy loads without seriously affecting their output, and thus are not typically used in such applications. For the test instrument in U.S. Pat. No. 4,074,195, for instance, the supply must be able to drive a signal transformer with loads on the secondary as heavy as 10 ohms, without the supply output being significantly affected.
Thus, it is a general object of the present invention to provide an oscillator circuit which can effectively operate as a power source for electrical instruments and similar devices.
It is another object of the present invention to provide such an oscillator circuit which is capable of providing a stable output under varying load conditions.
It is an additional object of the present invention to provide such an oscillator circuit which also functions as a high gain power amplifier.
It is a further object of the present invention to provide such an oscillator circuit which has an output with a very low DC component.
It is a still further object of the present invention to provide such an oscillator circuit which has a low output impedance.
It is yet another object of the present invention to provide such an oscillator circuit which is capable of self-correcting its output under varying load conditions.